The present invention relates to a controller for a variable pitch fan system, and more particularly to an electronic control device for selectively controlling a pitch of a variable pitch fan of the type capable of operating in a plurality of blade pitch positions, such as at least a neutral blade pitch position, a cooling blade pitch position, and a purge blade pitch position. The instant invention also relates to a method of selectively controlling a pitch of a variable pitch fan of the type capable of operating in a plurality of blade pitch positions, such as at least a neutral blade pitch position, a cooling blade pitch position, or a purge blade pitch position for controlling a direction of air flow to and from a cooling core.
Farms, feedlots, and other agricultural plots, as well as construction sites, mining sites, and other sites, are susceptible to producing large amounts of fine, particulate, airborne debris. These conditions present a problem for operators of agricultural vehicles such as trucks equipped with feed mixer bodies, tractors, bale pick up machines, silage baggers, composting machinery, bale grinding equipment and forage harvesters. As will be appreciated by those skilled in the art, a feed mixer body is a container having at least one agitator for mixing a plurality of livestock feeds to obtain a substantially uniform livestock feed mixture. Because these vehicles operate virtually non-stop, twenty-four hours a day, the cooling cores (e.g., radiators, oil coolers, air conditioning condensers, and heat exchangers) are constantly exposed to vast amounts of particulate debris. Because cooling fans ordinarily draw air in through the cooling core in a single constant direction to facilitate cooling of the fluid within the cooling core, the vehicle cooling cores often become clogged with debris when used in areas having high airborne particulate matter concentrations. Consequently, the engines of the vehicle may become overheated.
Similarly, in the recreational vehicle industry, there is a need for optimizing a fan actuating mechanism for cooling efficiency. In order to maximize energy efficiency of the cooling systems in recreational vehicles and the like are typically configured so that a fan is only actuated within very close temporal proximity to the time the motor has reached a maximum operating temperature, and will otherwise be shut down. A typical clutch fan is actuated by an engine electronic control module that is actuated by signals directly relating to vehicle temperature and other parameters that are hard coded into the engine electronic control module for activation. When actuated, these fans consume up to 50 engine horsepower. Since the timing of fan activation cannot be changed in the engine electronic control module by the vehicle operator, many of the manufacturers of recreational vehicles have incorporated direct drive fan systems, which is undesirable because it continually consumes up to 50 engine horsepower.
One known method for the removal of debris from the cooling cores of vehicles and other equipment operating in areas having high airborne particulate matter concentrations include requiring the vehicle or equipment operator to periodically interrupt his work, exit the cab of the vehicle, and manually clean out the debris-filled cooling core. Unless the operator periodically removes the debris in such a manner, the cooling core will become clogged, increasing the likelihood that the engine may consequently overheat or otherwise become inoperable.
A main drawback of manual removal of radiator debris is that the operator who is engaged in the task of distributing feed to livestock, for example, must periodically cease his operations to manually clear the cooling core of debris. Thus, manual removal of debris is time consuming and detracts from optimal work output of the operator. Moreover, this method subjects the operator to inclement weather, when present.
Another drawback of the above-identified conventional methods is that the operator must rely on memory to periodically remove the debris from the cooling core. If the operator neglects to remove the debris, the cooling core can quickly become clogged and cause damage to the engine.
Still another drawback of manual removal of debris is that the operator is subjected to hazards associated with cleaning the cooling cores. For example, the cooling cores can be heated to high temperatures, and are typically in close proximity to the extreme heat of the vehicle""s engine.
Yet another drawback of manual removal is that the equipment surrounding the cooling cores are susceptible to damage by the operator as the operator attempts manual removal. An example of this kind of damage is damage that may result to the cooling fins as manual removal is conducted.
Variable pitch fans are well known in the art, wherein fan blades of the variable pitch fan are capable of rotational movement to alter the pitch of the fan blade, and accordingly vary the direction of air flow through the fan blade. Examples of these variable pitch fans are those disclosed in U.S. Pat. No. 6,113,351, which is incorporated herein by reference and discloses a hydraulically powered variable pitch fan. U.S. Pat. No. 6,253,716 B1, which is incorporated herein by reference, discloses a pneumatically powered variable pitch fan.
In the ""716 patent, an actuator member is connected to each of the axially rotatable fan blade stems with a linkage configured so that linear movement of the actuator member causes axial rotation of the stems. The actuator member is biased to a first position by a spring. The first position represents one rotational extreme of the fan stems. A pneumatically-operated diaphragm is configured to engage the actuator member on an opposite side from the spring. Upon sufficient air pressure exerted against the diaphragm, the force exerted by the springs is overcome causing the stems to rotate to a second position. The amount of pitch may vary to achieve partial stem rotation.
A still further object of the invention is to provide an electronic control system for a variable pitch fan assembly that features the ability of detecting predetermined parameters and then signaling a valve assembly to alter the pitch of the variable pitch fan assembly.
The instant invention is directed to a method of selectively controlling a pitch of a variable pitch fan of the type capable of operating in a plurality of blade pitch positions, such as a at least a neutral blade pitch position, a cooling blade pitch position, and a purge blade pitch position for controlling a direction of air flow to and from a cooling core. The method includes the step of setting a predetermined parameter for temperature at a predetermined location, setting a predetermined parameter for air conditioner system pressure, and setting a predetermined parameter for time. In addition, the method detects when one of the predetermined parameters is reached, and signals at least one valve when one of the predetermined parameters is reached. Moreover, the method includes the step of energizing the at least one valve to alter the pitch of the variable pitch fan.
The instant invention is also directed to an electronic control device for selectively controlling a pitch of a variable pitch fan of the type energized by a valve assembly and capable of operating in a plurality of positions, such as at least a neutral blade pitch position, a cooling blade pitch position, and a purge blade pitch position, and includes a temperature detecting means for detecting a predetermined temperature at a predetermined location, and a pressure detecting means for detecting a predetermined pressure in an air conditioning system. The device also has a timer detecting means for detecting a predetermined time period, and a signaling means for signaling the valve assembly when a predetermined temperature, pressure or time period has been reached. The device further includes an energizing means for energizing the valve assembly.
The present invention further includes an electronic control device configured for altering the direction of air flow in response to factors relating directly to an increased temperature within the cooling core caused by debris accumulation or other factors. The electronic control device varies a pitch of a variable pitch fan assembly based on various parameters, such as a lapsing of a predetermined period of time, a detected increase in temperature at a predetermined location, or an increase in pressure within an air conditioning system.